U.S. Pat. No. 5,306,428 describes a work exchanger system as part of a reverse osmosis system such that, with the help of this work exchanger system, energy is recovered from the fluid, called the brine, which leaves reverse osmosis modules but still has a high residual pressure. The work exchanger system has a reversing valve with a rotating reversing element with the help of which the tubular chambers to be filled or emptied are switched. The rotating reversing element has a bypass opening to permit a controlled reduction in pressure between the tubular chambers to be filled and those to be emptied during the operation of reversing the work exchanger. However, this results in additional losses, which have an adverse effect on the efficiency of such a reverse osmosis system.
U.S. Pat. No. 5,797,429 discloses another design of a reversing valve for a work exchanger system. A reversing element is provided in the valve housing, and is constructed as a linearly displaceable control piston to reverse flow paths arranged radially with respect to the control piston. This approach attempts to improve upon a previous state of the art in which the filling and emptying operations in the tubular chambers were reversed with a plurality of valves in a complicated manner.
In the prior art devices, the alternating pressure loads and the resulting pressure surges produce a substantial material stress on all components. This reduces the service life of the valves, the tubular chambers and any individual reversing valves and requires material-intensive construction, accordingly. In addition, considerable annoying noises with negative consequences are produced during the reversing movements. Such a high noise level requires additional complex noise suppression measures and safety measures.